International Journal of Biological Macromolecules 105 (2017) 1241–1249 Contents lists available at ScienceDirect International Journal of Biological Macromolecules j ourna l h o mepa ge: www.elsevier.com/locate/ijbiomac Combined antibacterial/tissue regeneration response in thermal burns promoted by functional chitosan/silver nanocomposites E. Luna-Hernández a , M.E. Cruz-Soto b , F. Padilla-Vaca c , R.A. Mauricio-Sánchez a , D. Ramirez-Wong a , R. Mu˜ noz d , L. Granados-López d , L.R. Ovalle-Flores e , J.L. Menchaca-Arredondo e , A. Hernández-Rangel a , E. Prokhorov a , J.L. García-Rivas f , B.L. Espa ˜ na-Sánchez a,∗ , G. Luna-Bárcenas a,∗ a Departamento de Polímeros y Biopolímeros, CINVESTAV Unidad Querétaro, Libramiento Norponiente No. 2000, Fracc. Real de Juriquilla, C.P. 76230, Querétaro, Mexico b Escuela de Ciencias de la Salud, Universidad del Valle de México (UVM) Campus Juriquilla, Blvd. Juriquilla No. 1000, C.P. 76320, Querétaro, Mexico c Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta s/n Guanajuato, C.P. 36050, Guanajuato, Mexico d Departmento de Patología, Hospital Star Médica, Blvd. Bernardo Quintana No. 4060, Col. San Pablo, C.P. 76125, Querétaro, Mexico e Facultad de Físico Matemáticas, Universidad Autónoma de Nuevo León, Av. Universidad s/n, C.P. 66455, San Nicolás de los Garza, Nuevo León, Mexico f División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Toluca, Av. Tecnológico s/n Colonia Agrícola Bellavista, C.P. 52149, Metepec, Edo de México, Mexico a r t i c l e i n f o Article history: Received 20 April 2017 Received in revised form 25 July 2017 Accepted 26 July 2017 Available online 28 July 2017 Keywords: Antibacterial Tissue regeneration Chitosan/silver nanocomposites Thermal burns a b s t r a c t We report the combined antibacterial/tissue regeneration responses to thermal burns promoted by func- tional chitosan/silver nanocomposites (CS/nAg) with ultralow silver content (0.018 wt.%, 7–30 nm). Our approach allows one to produce CS/nAg nanocomposites without silver nanoparticles (nAg) agglomera- tion, with bactericide potency higher than 1 wt.% of nAg (ca. 10 nm) content and, promoting the healing process in controlled thermal burns. CS/nAg films exhibit high antibacterial activity against S. aureus and P. aeruginosa after 1.5 h of incubation, demonstrating the bacterial penetration into hydrated films and their interaction with nAg. Additionally, exceptional healing of induced thermal burns was obtained by increasing myofibroblasts, collagen remodeling, and blood vessel neoformation. These factors are asso- ciated with epiderma regeneration after 7 days of treatment with no nAg release. Our results corroborate the controlled synthesis of nAg embedded in CS matrix with combined antibacterial/biocompatibility properties aiming to produce functional nanocomposites with potential use in wound dressing and health care applications. © 2017 Elsevier B.V. All rights reserved. 1. Introduction Treatment of burn-injured patients has been considered an important clinical problem due to the fluid production and the persistency of pathogens during the healing process. In particular, thermal burn injuries are one of the most common form of trauma and cause severe skin damage with serious health consequences such as alteration of dermal cells, biomolecule homeostasis, tissue architecture and necrosis [1]. Conventional treatment of thermal wounds includes antiseptic techniques, topical medication and sur- ∗ Corresponding authors. E-mail addresses: lespana@cinvestav.mx (B.L. Espa ˜ na-Sánchez), gabriel.luna@cinvestav.mx (G. Luna-Bárcenas). gical removal of damaged skin to avoid bacterial contamination and to ensure healing. The most common infections presented in ther- mal burn injuries are produced by Gram-positive Staphylococcus aureus [2] and Gram-negative Pseudomonas aeruginosa [3], trig- gering significant cost to health care systems [4,5]. To accelerate the healing process in burns, different material alternatives have been explored including artificial skin [6], polymers [7], hydrogels [8], hybrid materials [9,10], among others. Some requirements of skin replacement consider a nonreactive organic polymer with high biocompatibility, adherence, high oxygen exchange, an efficient control of fluid transport and the avoidance of bacterial infections [5,11]. Recently, biopolymers such as chitosan (CS) have been used such as skin regenerator in third-degree burns [8]. CS [b-(1-4)-2-amino- 2-deoxy-d-glucose] is a linear poly-cationic heteropolysaccharide http://dx.doi.org/10.1016/j.ijbiomac.2017.07.159 0141-8130/© 2017 Elsevier B.V. All rights reserved.